diff --git a/CHANGELOG.md b/CHANGELOG.md
index e466e5442..2d50d4b1b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## Next
 
+- allow anonymous id generation to be configurable ([#133](https://github.com/PostHog/posthog-ios/pull/133))
+
 ## 3.3.0 - 2024-05-21
 
 - chore: apply patches from 3.2.5 to 3.3.0 and session recording fixes [#135](https://github.com/PostHog/posthog-ios/pull/135)
diff --git a/Package.resolved b/Package.resolved
index caad2dd4d..113b208ec 100644
--- a/Package.resolved
+++ b/Package.resolved
@@ -6,8 +6,8 @@
         "repositoryURL": "https://github.com/mattgallagher/CwlCatchException.git",
         "state": {
           "branch": null,
-          "revision": "3b123999de19bf04905bc1dfdb76f817b0f2cc00",
-          "version": "2.1.2"
+          "revision": "3ef6999c73b6938cc0da422f2c912d0158abb0a0",
+          "version": "2.2.0"
         }
       },
       {
@@ -15,8 +15,8 @@
         "repositoryURL": "https://github.com/mattgallagher/CwlPreconditionTesting.git",
         "state": {
           "branch": null,
-          "revision": "a23ded2c91df9156628a6996ab4f347526f17b6b",
-          "version": "2.1.2"
+          "revision": "2ef56b2caf25f55fa7eef8784c30d5a767550f54",
+          "version": "2.2.1"
         }
       },
       {
diff --git a/PostHog/PostHogConfig.swift b/PostHog/PostHogConfig.swift
index 924468906..e54df3ed1 100644
--- a/PostHog/PostHogConfig.swift
+++ b/PostHog/PostHogConfig.swift
@@ -26,6 +26,7 @@ import Foundation
     @objc public var captureScreenViews: Bool = true
     @objc public var debug: Bool = false
     @objc public var optOut: Bool = false
+    @objc public var getAnonymousId: ((UUID) -> UUID) = { uuid in uuid }
     /// Internal
     var snapshotEndpoint: String = "/s/"
 
diff --git a/PostHog/PostHogSessionManager.swift b/PostHog/PostHogSessionManager.swift
index 0c771f524..72ea396f2 100644
--- a/PostHog/PostHogSessionManager.swift
+++ b/PostHog/PostHogSessionManager.swift
@@ -12,8 +12,11 @@ class PostHogSessionManager {
 
     private let anonLock = NSLock()
     private let distinctLock = NSLock()
+    private let idGen: (UUID) -> UUID
+
     init(_ config: PostHogConfig) {
         storage = PostHogStorage(config)
+        idGen = config.getAnonymousId
     }
 
     public func getAnonymousId() -> String {
@@ -22,7 +25,7 @@ class PostHogSessionManager {
             anonymousId = storage.getString(forKey: .anonymousId)
 
             if anonymousId == nil {
-                anonymousId = UUID().uuidString
+                anonymousId = idGen(UUID()).uuidString
                 setAnonId(anonymousId ?? "")
             }
         }
diff --git a/PostHogTests/PostHogSessionManagerTest.swift b/PostHogTests/PostHogSessionManagerTest.swift
index 3ae343116..a445daebd 100644
--- a/PostHogTests/PostHogSessionManagerTest.swift
+++ b/PostHogTests/PostHogSessionManagerTest.swift
@@ -45,5 +45,16 @@ class PostHogSessionManagerTest: QuickSpec {
 
             sut.reset()
         }
+
+        it("Can can accept id customization via config") {
+            let config = PostHogConfig(apiKey: "123")
+            let fixedUuid = UUID()
+            config.getAnonymousId = { _ in fixedUuid }
+            let sut = PostHogSessionManager(config)
+            let anonymousId = sut.getAnonymousId()
+            expect(anonymousId) == fixedUuid.uuidString
+
+            sut.reset()
+        }
     }
 }